LAUSR

A simple and rapid reverse-phase high-performance liquid chromatographic method for the simultaneous separation and determination of erlotinib, an antineoplastic agent, which is used in the therapy of advanced or metastatic pancreatic or non-small cell lung cancer, and its metabolites has been developed. This method has been applied to urine and serum samples of patients under erlotinib treatment. After a dilution step, erlotinib and its metabolites have been separated on an Ultrabase 120 Å C18 column (4.6 mm i.d. × 150 mm, 5 μm) using methanol: 20 mM phosphate buffer pH 5.0 (60:40; v:v) as mobile phase at a flow rate of 1.4 mL min−1 and detected at 248 nm with a diode array detector. The limits of detection were between 2.1 and 5.1 ng mL−1. Within- and between-day accuracy and precision of the validated method were below the acceptable limits of 15% relative standard deviation at all concentrations tested. The quantitation method was successfully applied for the simultaneous determination of erlotinib and its metabolites in urine and serum samples from patients under clinical treatment of non-small cell lung cancer. The concentration ranges of erlotinib and desmethyl erlotinib in serum were 380–6510 and 66–558 ng mL−1, respectively, in patients under treatment. The objective is to propose a fast and simple method for a direct and reliable quantification of erlotinib and its metabolites in human urine and serum without previous sample treatment steps. The direct injection of diluted urine and serum can be highlighted as the greatest advantage that can be achieved by this method.Graphical abstract